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package com.sun.el.parser;

import java.util.List;
import javax.el.ELException;
import javax.el.ValueExpression;
import javax.el.LambdaExpression;
import com.sun.el.lang.EvaluationContext;
import com.sun.el.ValueExpressionImpl;
import com.sun.el.util.MessageFactory;

/**
 * @author Kin-man Chung
 */
public
class AstLambdaExpression extends SimpleNode {

    public AstLambdaExpression(int id) {
      super(id);
    }

    public Object getValue(EvaluationContext ctx) throws ELException {
        // Create a lambda expression
        ValueExpression expr =
            new ValueExpressionImpl("#{Lambda Expression}",
                                    this.children[1],
                                    ctx.getFunctionMapper(),
                                    ctx.getVariableMapper(),
                                    null);
        List<String>parameters =
            ((AstLambdaParameters) this.children[0]).getParameters();
        LambdaExpression lambda = new LambdaExpression(parameters, expr);
        if (this.children.length <= 2) {
            return lambda;
        }

        // There are arguments following the lambda exprn, invoke it now.
        Object ret = null;
        for (int i = 2; i < this.children.length; i++) {
            if (ret != null) {
                if (!(ret instanceof LambdaExpression)) {
                    throw new ELException(MessageFactory.get(
                        "error.lambda.call"));
                }
                lambda = (LambdaExpression) ret;
            }
            AstMethodArguments args = (AstMethodArguments) this.children[i];
            ret = lambda.invoke(ctx, args.getParameters(ctx));
        }
        return ret;
    }
}
